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Valentin [98]
3 years ago
7

Which is an example of a chemical change?

Chemistry
1 answer:
GenaCL600 [577]3 years ago
5 0
Bread baking in an oven
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A substance used as a cleaner and a fuel is 37.48% C, 49.93% O and 12.58% H by mass. A 0.2804-g sample of the substance occupies
andriy [413]

Answer:

Explanation:

We shall find out the molecular formula of the substance .

Ration of number of atoms of C , O and H

= \frac{37.48}{12} :\frac{49.93}{16} :\frac{12.58}{1}

= 3.12 : 3.12 : 12.58

= 1 : 1 : 4

volume of gas at NTP

= 250 x 273 / 350 mL .

= 195 mL .

Molecular weight of the substance = .2804 x 22400 / 195 g

= 32. approx

Let the molecular formula be

(COH₄)n  

n x 32 = 32

n = 1

Molecular formula = COH₄

The compound appears to be CH₃OH

a )

CO + 2H₂ = CH₃OH

28g     4g          32g

59      8

For 8 kg hydrogen , CO required = 56 kg

CO is in excess .  hydrogen is the limiting reagent .

mass of product formed

= 32 x 8 / 4

= 64 kg

b )

percentage yield = product actually formed / product to be formed theoretically  x 100

= 59.6 x 100 / 64

= 93.12 %

c )

2CH₃OH + 3O₂ = 2CO₂ + 4H₂O .

64 g                     2 x 22.4 L

Gram of gas in 1 gallon of fuel

= .7914 x 3785

= 2995.5 g

CO₂ produced at NTP by 2995.5 g CH₃OH

= 2 x 22.4 x 2995.5 / 64 L

= 2096.85 L

At 27° C and 766 mm Hg , this volume is equal to

2096.85 x 300 x 760 / 273 x 766

= 2286.18  L .

d )

C₈H₁₈  =  8CO₂

114g           8 x 22.4 L

gram of fuel per unit gallon

= .6986 x 3785

= 2644.2g

gram of CO₂ produced by 1 gallon of fuel  at NTP

= 8 x 22.4 x 2644.2 / 114

= 4156.5 L

So it produces more CO₂ .

7 0
4 years ago
What ia the difference between distilled water and tap water
Agata [3.3K]

<u>answer:</u> distilled water when you boil water, and turned into water vapor, then condense it back to it's liquid form. tap water is water that is from the valves or pipes. it can be used for everyday uses.

hope it helps❤ from peachimin

6 0
3 years ago
HELP ASAP PLEASE!!
Rudiy27

Answer:

the time in minutes

Explanation:

if the temp changes or not you cant stop time

3 0
3 years ago
Read 2 more answers
How many grams of a 22.9% sugar solution contain 68.5 g of sugar?
777dan777 [17]

    The grams  of 22.9 %   sugar  solution that contain 68.5  g  of   sugar  is 299.13 g  of  solution  

   <u><em>calculation</em></u>

 22.9%  means that  there are  22.9 g  of  sugar  in 100 g of solution.

   what about   68.5 g  of sugar

- <em>by cross    multiplication</em>

=[(68.5 g  sugar x 100  g  solution) /22.9  g sugar] =299.13 g  of solution

Nb; <em>g sugar cancel  each other</em>

5 0
3 years ago
how many grams of water are produced when 15 grams of magnesium hydroxide are reacted with sulfuric acid​
Mila [183]
<h3>Answer:</h3>

9.26 g of water

<h3>Explanation:</h3>

We are given;

  • 15 grams of magnesium hydroxide;

Required to calculate the mass of water produced;

We will use the following steps;

<h3>Step 1: Write the balanced equation for the reaction</h3>

Magnesium hydroxide reacts with sulfuric acid to produce water and magnesium sulfate;

Therefore, the equation of the reaction is;

Mg(OH)₂(aq) + H₂SO₄(aq) → MgSO₄(aq) + 2H₂O(l)

<h3>Step 2: Determine the number of moles of Mg(OH)₂ used </h3>

Number of moles = Mass ÷ Molar mass

Molar mass of Mg(OH)₂ =58.320 g/mol

Therefore;

Moles of Mg(OH)₂ = 15 g ÷ 58.320 g/mol

                             = 0.257 moles

<h3>Step 3: Calculate the moles of water produced</h3>

From the equation 1 mole of Mg(OH)₂ reacts to produce 2 moles of water;

Therefore; Moles of water = moles of Mg(OH)₂ × 2

Moles of water = 0.257 moles × 2

                         = 0.514 moles

<h3>Step 4: Calculate the mass of water produced;</h3>

Mass = Moles × Molar mass

Molar mass of water = 18.02 g/mol

Therefore;

Mass of water = 0.514 moles × 18.02 g/mol

                        = 9.26 g

Therefore, 9.26 g of water will be produced

3 0
3 years ago
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